Artificial Interruption Research Articles

Determination and Characterization of Preferential Water Flow in Unsaturated Subsoil of Andisol

Experimental approaches for directly determining preferential water flow in field soils usually require artificial interruption of the soil matrix's water flow. This interruption may change the quantitative as well as the qualitative nature of the preferential water flow, particularly in soils such as Andisols where matrix water flow is the dominant process of drainage. To overcome this problem, we applied both the one-dimensional form of Darcy's equation and the soil water balance method, during and shortly after each rain event, for characterizing as well as determining the preferential water flow across a depth of 1 m in an Andisol. The volumetric water contents and pressure potentials at different soil depths were monitored by time domain reflectometry and tensiometry during a 7-yr period. Preferential water flow was detected only two to seven times per year; nevertheless, it accounted for 16 to 27% of the annual total drainage. These flows occurred under macroscopically homogeneous soil water conditions, with pressure potentials mostly below the air-entry pressure in the subsoil. The in situ unsaturated hydraulic conductivity at the depth of 1 m, determined to apparently explain the total drainage during a preferential water flow event, varied over more than one order of magnitude, with little change in water content, and the maximum value reached the saturated hydraulic conductivity. This indicates that preferential water flow occurred mainly through the largest macropores at this depth due to pore-scale physical nonequilibrium. Macropore-mediated preferential water flow and solute transport should be considered in unsaturated subsoil of Andisols.

Determination and Characterization of Preferential Water Flow in Unsaturated Subsoil of Andisol

Experimental approaches for directly determining preferential water flow in field soils usually require artificial interruption of the soil matrix's water flow. This interruption may change the quantitative as well as the qualitative nature of the preferential water flow, particularly in soils such as Andisols where matrix water flow is the dominant process of drainage. To overcome this problem, we applied both the one‐dimensional form of Darcy's equation and the soil water balance method, during and shortly after each rain event, for characterizing as well as determining the preferential water flow across a depth of 1 m in an Andisol. The volumetric water contents and pressure potentials at different soil depths were monitored by time domain reflectometry and tensiometry during a 7‐yr period. Preferential water flow was detected only two to seven times per year; nevertheless, it accounted for 16 to 27% of the annual total drainage. These flows occurred under macroscopically homogeneous soil water conditions, with pressure potentials mostly below the air‐entry pressure in the subsoil. The in situ unsaturated hydraulic conductivity at the depth of 1 m, determined to apparently explain the total drainage during a preferential water flow event, varied over more than one order of magnitude, with little change in water content, and the maximum value reached the saturated hydraulic conductivity. This indicates that preferential water flow occurred mainly through the largest macropores at this depth due to pore‐scale physical nonequilibrium. Macropore‐mediated preferential water flow and solute transport should be considered in unsaturated subsoil of Andisols.

Application of operating vehicle load to structural health monitoring of bridges

For health monitoring purpose usually the structure is instrumented with a large scale and multichannel measurement system. In case of highway bridges, operating vehicle could be utilized to reduce the number of measuring devices. First this paper presents a static damage detection algorithm of using operating vehicle load. The technique has been validated by finite element simulation and simple laboratory test. Next the paper presents an approach of using this technique to field application. Here operating vehicle load data has been used by instrumenting the bridge at single location. This approach gives an upper hand to other sophisticated global damage detection methods since it has the potential of reducing the measuring points and devices. It also avoids the application of artificial loading and interruption of any traffic flow.

Characterising the visual buffer: real-world evidence for overwriting early in each fixation.

What happens to the pictorial content of fixations when we move our eyes? Previous studies demonstrate that observers are very poor at detecting changes in natural scenes that occur across saccades, blinks, and artificial interruptions ('change blindness'). They suggest that the visual 'snapshots' of what is on the retina during a fixation are not retained and fused over successive fixations. I find similar results when volunteers are performing the complex real-life task of making a cup of tea. Volunteers can access the snapshot of the current fixation but not those of previous fixations. I suggest that volunteers are reporting the content of a low-level visual store that holds a veridical snapshot of the current fixation, rather than the retina itself. The snapshots are not 'wiped' by the saccade and remain in the buffer until they are overwritten by a new snapshot. The overwrite occurs in an all-or-none manner and can be at any time within the first 400 ms of each new fixation, with 50% of overwrites being within the first 100 ms.

Adaptive control of copulation duration by males under sperm competition in the mite, Macrocheles muscaedomesticae

In a manure-inhabiting predatory mite, Macrocheles muscaedomesticae (Gamasida, Macrochelidae), when the female mates with two males, the first male takes nearly perfect fertilization priority (Yasui, 1988). The present study examined whether the first-male's sperm precedence is influenced by the copula-duration of the first and second males mating with the same female, and whether males control their copulation duration by assessing the probability that the mate has been inseminated by other males. Results of the artificial interruption of copulation showed that sperm precedence value, P2 (the proportion of the offspring fathered by the second male), was negatively correlated with the copulation duration of the first male but positively correlated with that of the second male. There was a threshold (ca. 180–300 seconds) in the first-male's copulation duration beyond which P2 decreased drastically; when length of the first copulation exceeded this threshold, the second males did not fertilize eggs, whereas they fertilized more than half of the eggs when the first-copulation duration was shorter than the threshold. Almost all males copulated for a longer period (average 509.8 seconds) than this threshold if the copulation duration of the previous male had not exceeded the threshold, but if it was longer than the threshold, second males had shortened their copulation (67.6 seconds). These results suggest that males are able to assess the insemination status of their mates and to adjust their copulation duration depending on the probability of fertilizing eggs by their own sperm. A mechanistic explanation for sperm precedence (i.e., plug-formation within sperm receptive organ of the females) is proposed.

Copulation duration and sperm precedence in the stalk-eyed fly Cyrtodiopsis whitei (Diptera : Diopsidae)

By means of field observations and laboratory experiments on the Malaysian stalk-eyed fly Cyrtodiopsis whitei we examined the consequences of variation in copulation duration for sperm competition. In this sexually dimorphic species over 90% of all copulations occur in nocturnal aggregations with from one to four males and up to 24 females. Copulation duration observed in both the field and the laboratory exhibited a bimodal distribution with peaks at 10 and 50 s. In the field short copulations less than 30 s long occurred frequently when more than one male was present in an aggregation but most were not the direct result of male interference. Sperm counts from female spermathecae after artificial interruptions indicated sperm are not transferred during the first 40 s of a copulation. When solitary males mated up to five times in succession to virgin females, short copulations did not occur, nor was the number of sperm transferred reduced. However, short copulations did occur when we mated isolated females within 6 min of a previous copulation. By mating irradiated and non-irradiated males in reciprocal pairs we discovered that C. whitei exhibits both first-male sperm precedence and sperm mixing. More than half of the females mated first to sterile and then to fertile males failed to produce offspring. Such variation in copulation duration and sperm precedence is consistent with male placement and detection of a spermatophore that acts as a temporary mating plug. Our data suggest that those male C. whitei which successfully defend large aggregations of females reduce sperm waste and competition by preferentially transferring sperm to females that have not mated recently.

Structural changes of the human embryonal cortex during explantation.

It has been shown in numerous studies on the transplantation of neocortical anlagen of mammals that processes of cytodifferentiation proceed successfully in the grafts, but that the cytoarchitectonics are disturbed. This may be associated with the formation of closed cavities lined with neuroepithelium [12], the so-called rosettes, in the early period following transplantation. The rosettes become the centers of proliferation from which cells which have completed division diverge in all directions instead of migrating to the cortical plate [2]. Information regarding the initial stages of the formation of rosettes is lacking in the literature. The purpose of the present study was to investigate the early changes in areas of the wall of the telencephalic vesicle of human embryos and the formation in it of rosettes under the conditions of explantation. Materials and Methods. The material for explantation was taken from 7-11-week old human fetuses obtained following artificial interruption of pregnancy in the clinic. The possibility of the use of medium 199 for the study of the morphogenetic mechanisms during explantation to it of anlagen of the neural tube of chick embryos has been demonstrated by a number of authors [10, 11]. This medium has been used in this study as well. Whole embryos (7-8 weeks) or fragments of the telencephalon broken off during the abortion (9-11weeks) were placed in the medium, cooled to 0-4~ for transportation. The dorsolateral sections of the walls of the cerebral hemispheres were freed from the pia mater under laboratory conditions, cut into pieces, from 1 to 10 mm in diameter, which were transferred to a fresh portion of medium with the addition of penicillin and cultured at 37~ In the process each explant was placed into a drop of medium on a slide; after it was sucked up with a pipette, Bouin's fluid was applied to the preparation. The fixed material was treated by two methods. A portion of the material was used to obtain histological sections (thickness 7 ~rn, staining with hematoxylin-eosin). The other portion of the material, following a one-hour bath in distilled water, was embedded in a 1% solution of silver nitrate for one to two days, following which each of the pieces was treated with a standard solution of a developer for photographic film (the Ramon y Cajal method). The relief of the surface of the explant was clearly demonstrated using raking illumination from above. Side-lighting with a narrow beam of light was used for the intravital investigations of the explants. Investigation Results and Discussion. Numerous fissures on the ventricular surface were found in the initial material in the total preparations, both impregnated with silver nitrate (Fig. la), and in the intravital observations. The occurrence of fissures is apparently caused by manipulations during the interruption of pregnancy and during the opening of the brain vesicles during the preparation of the material for explantation. The fissures are observed in all of the fetuses from 7 to 11 weeks of development. At the same time, the surface facing the pia mater remains smooth. The depth of the fissures is varied (see Fig. lb): In some cases they penetrate only to the middle of the ependymal zone (of the neuroepithelium); in others, they reach the intermediate layer. Not infrequently, dead cells with pyknotic nuclei are found in the region of the fissures. Undamaged smooth sections of the ventricular surface of the neuroepithelium are visible between the fissures. In the number of instances the borders of such sections are raised above the general surface of the explant. Noticeable changes do not take place during the first hour of cultivation at 37~ The degeneration of neuroblasts in the cortical zone is observed only in some instances. After 3-6 h (see Fig. lc) the borders of the fissures are somewhat raised, forming ridges. It can be seen in the sections (see Fig. ld) that the free edges of the neuroepithelium which are everted toward the ventricular surface correspond to the ridges, while the fissures themselves begin to fill with cells probably arising from the intermediate zone. The degeneration of neuroblasts in the cortical and especially in the subcortical zones is well seen at this stage. After 12-24 h, the fissures gradually close over, while the ridges surrounding them reach maximal development (see Fig. le). Where the fissures are located close to one another, their

Transplantation of human embryonal nervous tissue into the spinal cord of adult rats

human embryos, containing an anlage of the neocortex can be used as the initial material for transplantation [3, 4]. It has been placed into the cerebral cortex of adult rats, and the taking of the graft has been observed [5]. The time course of the proliferative processes and the differentiation of the cellular elements have been studied in this model, and it has been demonslrated that the prolonged existence, for six months and longer, of the trap. splant without signs of a cellular immune reaction is possible in a number of instances. The purpose of the present investigation was the elucidation of the characteristics of the development of a transplant of human embryonal nervous tissue in the rat spinal cord. Taking the great potentials for growth of segments of the telencephalic vesicles of human embryos, and data regarding the fact that they take well in homografts of the spinal cord of mammals [3, 4, 8, 7], into account, this division of the embryonal brain was specifically selected as the initial material for transplantation. Material and Methods. The investigation was carried out on 68 adult Wistar rats, weighing 200-250 g. Laminectomy of the VI thoracic vertebra was carried out in the animals under anesthesia (Calypsol in a dose of 200 mg/kg in combination with the inhalation of ether vapors). With monitoring by means of an operative microscope, the dura mater was opened, and a segment of donor brain measuring 2 mm 3 was introduced by a means of a glass cannula with an internal diameter of 0.5 mm into the spinal cord. Segments of the wall of the telencephalic vesicle of human embryos at the 8-10 week period of development, obtained after artificial interruption of pregnancy, were transplanted. The initial material for the transplantation was kept for several hours in Hanks' solution at t ~ = 4~ After the operation the animals were maintained in the usual vivarium conditions. Morphological investigation using light and electron microscopic methods was carried out 2, 3, 4, 8, and 12 weeks later. For light microscopy the material was fixed in Bouin's fluid. Paraffin sections, 5-7 Inn were stained with hematoxylin-eosin and toluidine blue after Nissl. For the electron microscopy, fixation of the brain was carried Out by perfusion of a 2.5% solution of glutaraldehyde in a 0.01 M phosphate buffer at pH 7.3-7.4, with subsequent treatment with a 2% solution of OsO4 in a 0.05 M cacodylate buffer, The material dehydrated in a series of alcohols of increasing concentration and in propylene oxide, and mounted in Epon. After the semithin sections were studied, collimated trimming of the blocks was carried out. The ultrathin sections, 50 nm in thickness, were obtained on an LKB ultratome, and studied under a JEM 100-B electron microscope. Results and Discussion. The wall of the telencephalic vesicle of the donor embryo at the 8-10 week period of development consists of cells of various degrees of maturity. Undifferentiated neuroepithelial cells, capable of mitotic division, are located in the ventricular zone. They are the forerunners of both nerve and glial cells. These cells, which are capable of migration, have an elongated form when stained with hematoxylin-eosin. A large number of mitotically dividing cells are observed particularly in the ventricular zone. The anlage of the ncocortex, the primary gray matter of the cortex, properly appears in embryogenesis from the eighth week of intrauterine development as a result of the migration of cells from the ventricular zone [1, 6]. It consists of cells of a high degree of maturity. As the formation of the primary gray matter of the cortex and the increase in the number of cells

THE DIAGNOSTIC VALUE OP PARTIAL FLOW-VOLUME CURVES IN INFANTS WITH AIRWAYS OBSTRUCTION

The performance of flow-volume (FV) curves in infants is usually associated with considerable expense, in order to achieve a controlled forced expiration. The inspiratory portion of FV curves is usually neglected. In our lung function laboratory FV curves were recorded in slightly sedated infants during spontaneous breathing. Furthermore, FV curves were recorded immediately after a short artificial interruption of breathing, at the end of inspiration, resp. expiration. In addition, body plethysmography was done. The findings were compared with the results of clinical and - in 18 cases - endoscopical examinations. Tests in 108 infants with and without cardiorespiratory disease showed that the configuration of FV curves allows conclusions on the kind and extent of airways obstruction similar to those in adults: Distinct limitation of inspiratory flow is caused by an extrathoracic stenosis; a low expiratory flow with a very strict linear or a curvilinear course suggests an intrathoracic impairment of airways. The sensitivity in the diagnosis of an airways obstruction is inferior to that of body plethymography. Specifity is high, if the results are compared with clinical and endoscopical findings. Thus, valuable information on ventilation is obtained by means of a simple method.

Inhibition of the Lytic Action of Cell-bound Terminal Complement Components by Human High Density Lipoproteins and Apoproteins

Human serum lipoproteins are known to participate in or modify several immunologically relevant responses, including the inhibition of target cell lysis initiated by fluid-phase C5b-7 (reactive lysis). We now report that human high density lipoproteins (HDL) can inhibit the complement (C) lytic mechanism after C5b-7, C5b-8, and even C5b-9 have been bound to the target membrane. This inhibitory activity of serum or plasma copurifies in hydrophobic chromatography with antigenically detected apolipoprotein A-I (apoA-I), the major HDL apoprotein, and with HDL in CsCl density gradient ultracentrifugation. Although HDL is more active than its apoproteins in fluid-phase inhibition of C5b-7-initiated reactive lysis, the HDL apoproteins are more effective after C5b-7, C5b-8, or C5b-9 have become bound to human or sheep erythrocytes (E). Highly purified HDL apoproteins, apoA-I and apoA-II, both have greater inhibitory activity than whole HDL on a protein weight basis, and some evidence has been obtained that apoA-I dissociating spontaneously from HDL may be the principal inhibitory moiety in physiological situations. HDL lipids themselves are inactive. The HDL-related inhibitors are ineffective when incubated with EC5b-7 and removed before C8 and C9 are added, and only minimally effective on cell-bound C5b-8 sites before C9 is added. They exert their most prominent inhibitory activity after C9 has been bound to EC5b-8 at low temperature, but before the final temperature-dependent, Zn(++)-inhibitable membrane damage steps have occurred. Therefore, HDL or its apoproteins do not act to repair already established transmembrane channels, but might interfere either with insertion of C9 into the lipid bilayer or with polymerization of C9 at C5b-8 sites. This heat-stable inhibitory activity can be demonstrated to modify lysis of erythrocytes in whole serum, i.e., it does not depend upon artificial interruption of the complement membrane attack sequence at any of the above-mentioned stages. Contributions of the target membrane itself to the mechanism of inhibition are suggested by the observations that, in contrast to sheep or normal human E, lysis of guinea pig E or human E from patients with paroxysmal nocturnal hemoglobinuria is inhibited poorly. This is the first description of a naturally occurring plasma inhibitor acting on the terminal, membrane-associated events in complement lysis. Although further study is required to assess the physiologic or immunopathologic significance of this new function of HDL, the HDL apoproteins or their relevant fragments should be useful experimentally as molecular probes of the lytic mechanism.

Sanctions for Performing Illegal Abortions

Criminal sanctions for performing illegal abortions are provided for in Article 116 of the Criminal Code of the RSFSR. Abortion means artificial interruption of pregnancy at any stage. An abortion is regarded as illegal if performed in violation of specified conditions. In accordance with the edict of the USSR Supreme Soviet Presidium, November 23, 1955, "On Repeal of the Prohibition of Abortions," artificial interruption of pregnancy is permissible only in hospitals and other health institutions in accordance with the Instruction of the USSR Public Health Ministry issued November 29, 1955, "On the Procedure for Performing the Operation of Artificial Interruption of Pregnancy [Abortion]." An abortion is regarded as contrary to law if it is performed other than in an inpatient institution, if the operation is performed by a person without higher medical education, or if there are medical contraindications in the pregnant woman for that operation.

Influence of simultaneous low amniotomy and oxytocin infusion and other maternal factors on neonatal jaundice: a prospective study.

In a prospective study of 196 consecutive single births a significant increase in serum bilirubin concentrations was found in infants born after low amniotomy induction and oxytocin infusion compared with those born spontaneously. This relationship was not dose-dependent and may have been associated with artificial interruption of pregnancy rather than the oxytocin itself. Infants delivered after spontaneous labour accelerated by oxytocin showed no such increase. The hormonal surge at the spontaneous onset of labour may affect fetal enzyme induction, but other factors, such as methods of infant feeding and oral contraceptive use, were found not to be significant.

INCREASED BILIRUBIN LEVELS IN NEONATES AFTER INDUCTION OF LABOUR BY INTRAVENOUS PROSTAGLANDIN E 2 OR OXYTOCIN

Four groups of thirty primigravidas and their infants were studied prospectively. Group A had labour induced by intravenous oxytocin, group B by intravenous prostaglandin E 2, and group C by extra-amniotic prostaglandin E 2. In the fourth group (D), labour was spontaneous throughout. Mean bilirubin levels on day 5 were significantly higher in groups A and B than in group D. The level in group C did not differ significantly from groups A, B, or D, although the mean inducibility rating in this group was lower. The mean serum-bilirubin level was significantly lower after cæsarean section than after assisted vaginal delivery. Mean serum-bilirubin levels were not affected by the previous use of oral contraceptives, maternal smoking-habits, or methods of infant feeding. The data suggest that the neonatal hyperbilirubinæmia observed may be due to the artificial interruption of pregnancy, although a direct drug effect cannot be excluded.

The artificial interruption of pregnancy: Bué, V.: L'Écho Médical du Nord. 23: 269, 1929

The artificial interruption of pregnancy: Bué, V.: L'Écho Médical du Nord. 23: 269, 1929

On artificial interruption of pregnancy with pulmonary tubercles

Numerous observations have established that pregnancy, childbirth and the postpartum period have an extremely detrimental effect on the course of the pulmonary tubercle.